1. Field
This application relates generally to networking and, more particularly, to routing data traffic within a communications networking system.
2. Background Information
As used herein, the term “Fibre Channel” refers to the Fibre Channel family of standards (hereinafter referred to as “Fibre Channel”) developed by the American National Standards Institute (ANSI). In general, Fibre Channel defines a transmission media based at least in part on high speed communications interfacing for the transfer of large amounts of data via communicatively coupled devices, including, for example, such devices as personal computers, workstations, servers, mainframes, supercomputers, and storage devices. Use of Fibre Channel, the Fibre Channel protocol, or the Fibre Channel standard, all of the foregoing used interchangeably throughout this specification, is proliferating in a variety of applications, including, for example, client/server applications which may, for example, employ high bandwidth and/or low latency input/output techniques. Examples of such applications include mass storage, medical and scientific imaging, multi-media communications, transactions processing, distributed computing and distributed database processing applications, just to name a few.
Although the claimed subject matter is not limited in scope to systems that are compliant with the Fibre Channel set of standards, it provides a helpful reference point with respect to network data communications. For systems that are Fibre Channel compliant, for example, communications between devices is typically facilitated over a switch fabric. The switch fabric is typically constructed from one or more Fibre Channel compliant switches or other devices. In one such structure, each device may be coupled to the fabric. Thus, devices coupled to the fabric are capable of communicating with the other devices coupled to the fabric, although, of course, this is merely an illustrative example and the claimed subject matter is not limited in scope to such an example.
However, one disadvantage of Fibre Channel compliant protocol devices is that frame traffic between a source device and a destination device are to be delivered “in-order” as part of being Fibre Channel compliant. Unfortunately, however, in a variety of circumstances, “in-order” delivery may result in frame routing techniques that result in increased congestion and/or delay over what might occur if “in-order” delivery of frames or packets were not accommodated.
To provide an example, certain traffic patterns in a fabric may result in active routes being allocated to particular or selected available paths thereby creating a high probability of congestion. It would be more desirable, instead, if, for example, frame traffic could be at least roughly evenly distributed across available paths; however, to result in “in-order” delivery, frequently, frame traffic is allocated to a single available path or to a subset of the available paths. A need therefore exists to reduce frame traffic congestion and/or to provide greater balance of frame traffic across a variety of available paths while maintaining “in-order” delivery of frames.